Darcy's Possibly Happy Childhood

Because Darcy is glum and untalkative, some fan fiction tries to suggest that he has trauma.

I don't agree (and neither does Darcy, actually).

Austen siblings often have close relationships.
Henry & Eleanor Tilney protect each other,  
& their rakish brother, against their father.

It is customary to give heroes and heroines difficult family relationships. After all, it is more dramatic! And, to be fair, a number of Austen's characters do have dysfunctional home lives: Anne Elliot, Henry Tilney, Edmund Bertram, and Elizabeth herself. On the other hand, Catherine Morland, the Musgroves, Elinor's immediate family, and Emma all have good relationships with their families.

Even those without good relationships rarely spend time agonizing over their family issues--not a lot of Freudians in this crowd!

Darcy is one of Austen's characters who had a very happy childhood. His own description follows:

As a child I was taught what was right, but I was not taught to correct my temper. I was given good principles, but left to follow them in pride and conceit. Unfortunately an only son (for many years an only child), I was spoilt by my parents, who, though good themselves (my father, particularly, all that was benevolent and amiable), allowed, encouraged, almost taught me to be selfish and overbearing; to care for none beyond my own family circle; to think meanly of all the rest of the world; to wish at least to think meanly of their sense and worth compared with my own.

In other words, Darcy's pride though partly the result of how he was raised is not in any way the result of poor treatment: neglect or abuse.

Not only is Darcy's pride not the result of poor treatment; it isn't even the result of deliberate brainwashing: "Son, you are better than anyone else; don't you forget it!" Darcy's pride is actually much closer to that described by C.S. Lewis in The Screwtape Letters. In a letter to Wormwood, Screwtape suggests how to exacerbate (spiritual) pride:

[She makes the] quite untroubled assumption that the outsiders who do not share [her beliefs] are really too stupid and ridiculous...it is not, in fact, very different from the conviction she would have felt at the age of ten that the kind of fish knives used in her father's house were the proper or normal or "real" kind, while those the neighboring families were "not real fish knives" at all. Now the element of ignorance and naivete in all this is large...

Screwtape then goes on to discuss how Wormwood can use this perspective to push the cliquey idea of "us versus them."

The attraction of a clique or set to someone like Darcy is not the attraction of being superior to others ("We are so much more beautiful, successful, likable than you"), which is the Crawfords' type of pride in Mansfield Park. For Darcy the attraction of the clique lies in MY family, MY friends, MY people versus Mrs. Bennet, Mr. Collins, Lady Catherine, etc. etc. etc. 

Darcy's "MY" extends from his happy childhood.